An investigation into the effects of residual water on the glass transition temperature of polylactide microspheres using modulated temperature DSC

Passerini, N and Craig, D.Q.M (2001) An investigation into the effects of residual water on the glass transition temperature of polylactide microspheres using modulated temperature DSC. Journal of Controlled Release, 73 (1). pp. 111-115.

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Abstract

The objective of the study was to ascertain residual water levels in polylactide and polylactide-co-glycolide microspheres prepared using the solvent evaporation technique and to investigate the effects of that water on the glass transitional behaviour of the microspheres. Microspheres were prepared from polylactic acid (PLA) and polylactide-co-glycolide (PLGA) 50:50 and 75:25 using a standard solvent evaporation technique. The glass transition was measured as a function of drying conditions using modulated temperature DSC. The microspheres were found to contain very low levels of dichloromethane, while residual water levels of up to circa 3% w/w were noted after freeze or oven drying, these levels being higher for microspheres containing higher glycolic acid levels. The residual water was found to lower the Tg following the Gordon–Taylor relationship. The data indicate that the microparticles may retain significant water levels following standard preparation and drying protocols and that this drying may markedly lower the Tg of the spheres.

Item Type: Article
Uncontrolled Keywords: plasticization,microsphere,glass transition,polylactic acid,modulated temperature differential scanning calorimetry
Faculty \ School: Faculty of Science > School of Pharmacy
Related URLs:
Depositing User: Rachel Smith
Date Deposited: 15 Mar 2011 16:16
Last Modified: 24 Jul 2019 17:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/25866
DOI: 10.1016/S0168-3659(01)00245-0

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